I just got back from NZ and what we did was work for Bliss stick on the north island, they are awsome people there and we had a great time staying there and working. Call ahead of time and set something up with them, but the way it worked for us is that we worked for a week in exchange for a boat for 500 NZ. With the exchange rate this is an amazing deal, plus it was exciting building your own boat. They like to take people on like us because it's cheep labor and it gets there boats out there for advertising.
I dont think I would have had a problem selling my boat when I came back but i didn't want to part with it so I brought it home. It was a pain in the ass to say the least. I had some special flight situations which made it more of a pain in the ass, but it still would have costed a lot. I had to get a flight from christchurch to aukland then auckland to LA and LA to denver. At each one of these stops I had to get my luagage and boat and go check in again, so I had to pay each time, not to mention lug my boat through every airport. If you only had to check in once to get back to the US I think it would be worth it but I wouldn't do what I did again.
Hope this helps.... go check out blisstick you will have a good time.